Actuators are relatively simple mechanical components that are often incorporated into more complex mechanical systems, including those found in automobiles, aircraft, manufacturing facilities, and processing facilities. A conventional solenoid is one example of an actuator that has found broad application across many types of industries and technologies.
With respect to aerospace structures in particular, morphing aerospace structures can be achieved using several approaches: by using fixed shape components and actuators which will move those fixed shaped components; by using variable shape materials (i.e., morphing materials); and by using combinations thereof. It would be desirable to provide morphing materials capable of accommodating relatively large deformations while also exhibiting relatively high mechanical strengths, for use in aerospace structures and other applications.
Electroactive polymers, shape memory alloys (SMA), and shape memory polymers (SMP) exhibit such desirable properties. Electroactive polymers generally require a relatively bulky power unit. SMAs and SMPs can change shape in response to temperature changes. Performance of such active materials can be evaluated in terms of specific active strain, which is the maximum strain divided by the weight of the active material and required infrastructure (i.e., any power supply required, or means for controlling temperature). Both SMAs and SMPs can provide relatively high specific active strain.
Aerospace structures (whether implemented using fixed shape materials or morphing materials) often require a reversible change between two configurations. Unfortunately, SMAs and SMPs generally exhibit a one-way shape memory property, which is not ideal for reversible morphing structures. It would be desirable to enable techniques for using one-way SMAs and SMPs in structures requiring a reversible change between two configurations. Such structures will likely find application in aerospace and medical industries.